基于触摸式一体机的仪表综合试验台设计

文章从硬件设计和软件开发两方面描述了触摸式一体机仪表综合试验台的研发。通过基于Windows CE操作系统下的控制平台,实现了仪器仪表测量数据的自动保存及打印功能。     

百色水利枢纽消力池底板抗浮稳定计算与分析

根据百色水利枢纽“表孔宽尾墩＋中孔跌流＋底流式消力池”联合消能工的特点，结合消力池地质条件的复杂性，利用消力池底板动水荷载模型试验成果，考虑止水失效工况，进行底板抗浮稳定计算和分析。     

How much do plant guarantees reduce perceived risk?

Abstract

Consumers do perceive risk in purchase decisions and seek to reduce both uncertainty and probability of loss. Risk also varies across persons and purchasing situations. Retailers promote product guarantees as risk reducers, but the quantitative evidence is lacking. They offer guarantees to help resolve outcomes from post-purchase problems mainly, product performance. We used an online survey to investigate the role of risk mitigation by money-back guarantees (MBGs) on a live product: plants. We obtained online responses from 504?US residents?≥?age 18 years who had made at least one live plant purchase in the six months prior to the study. As MBG length increased, perceived risk (PR) decreased. PR was higher for men than for women and declined as income increased. Subjects with a higher level of product involvement, expertise, delight, repurchase intentions, and regret had a higher level of PR. We conducted separate Chow tests for annual and perennial plants by price and MBG length and found several break points. As price increased from $5 to $10, a 30-d MBG reduced PR for annual plants while the reduction in PR was incrementally decreased for all guarantee lengths when annuals were priced over $20. With perennial plants, the MBG had an increasingly larger effect on reducing PR for each $10 increase in price. Overall, for each day increase in MBG length, we observed a 0.0337 decrease in PR, which meant that a 90-d MBG on a plant would reduce PR by 3%. This quantitative evidence of reduction in PR should encourage the use and communication of MBGs which have the potential to improve purchases, customer retention, and profitability.     

A framework for assessing financial stability?

I worked as a consultant in the Financial Stability Department (FSD) of the Bank of England for several years (2002–2004). In this paper I reflect on issues relating to the work of such an FSD, starting with the difficulty of defining or measuring ‘financial stability’. Stress tests are commonly used, but, for an FSD, should relate to the system as a whole, not just to individual institutions. FSDs need to assess the probability, virulence and speed of occurrence of potential shocks. There is a need to develop appropriate analytical models. The focus on capital adequacy has diverted attention from concern about having sufficient liquidity.     

化学法二氧化氯发生器转化率测定方法的研究

为衡量化学法二氧化氯发生器运行费用,分析发生器产物的成分、计算产率、二氧化氯转化率等性能指标,本文设计研究了化学法二氧化氯发生器的二氧化氯转化率、氯酸钠耗率等的测定方法.采取恒定进口原料溶液的流量,时监测出口吸收水溶液流量和取样分析各组分浓度,以抵消原料在反应器停留时间的影响,对商品化学法复合型二氧化氯发生器在应用现场进行了实际测定.结果显示出口溶液流量波动也会影响个别结果.选择的两个分析方法测定有效氯结果无显著性差异.整体试验结果在可接受范围     

Sequential control of time series by functionals of kernal-weighted empirical processes under local alternatives

Motivated in part by applications in model selection in statistical genetics and sequential monitoring of financial data, we study an empirical process framework for a class of stopping rules which rely on kernel-weighted averages of past data. We are interested in the asymptotic distribution for time series data and an analysis of the joint influence of the smoothing policy and the alternative defining the deviation from the null model (in-control state). We employ a certain type of local alternative which provides meaningful insights. Our results hold true for short memory processes which satisfy a weak mixing condition. By relying on an empirical process framework we obtain both asymptotic laws for the classical fixed sample design and the sequential monitoring design. As a by-product we establish the asymptotic distribution of the Nadaraya-Watson kernel smoother when the regressors do not get dense as the sample size increases.Acknowledgements The author is grateful to two anonymous referees for their constructive comments, which improved the paper. One referee draws my attention to Lifshits paper. The financial support of the Collaborative Research Centre Reduction of Complexity in Multivariate Data Structures (SFB 475) of the German Research Foundation (DFG) is greatly acknowledged.     

On the finite sample behavior of testing whether new is better than used of a specified age

Hollander, Park and Proschan (1986) proposed a test of new is better than used of a specified age. It is based on large sample normality of the test statistic. There is, however, no study in the literature on its actual size for small and moderate sample sizes. To shed some lights on this, the results of a Monte Carlo simulation study as well as two real data examples are reported and these indicate that the test can have a quite liberal size, especially for small to moderate sample sizes. In order to improve on this weakness, a modified test is proposed and studied. It is noticed that this modified test seems to over-correct the original test to an extent that it becomes unduly conservative sometimes. Hence we propose another modification that combines the original test and the modified test turns out to have its size quite close to the nominal level and is therefore preferable to both the original and modified tests.     

Non-convex Technologies and Cost Functions: Definitions,Duality and Nonparametric Tests of Convexity

This contribution is the first systematic attempt to develop a series of nonparametric, deterministic technologies and cost functions without maintaining convexity. Specifically, we introduce returns to scale assumptions into an existing non-convex technology and, dual to these technologies, define non-convex cost functions that are never lower than their convex counterparts. Both non-convex technologies and cost functions (total, ray-average and marginal) are characterized by closed form expressions. Furthermore, a local duality result is established between a local cost function and the input distance function. Finally, nonparametric goodness-of-fit tests for convexity are developed as a first step towards making it a statistically testable hypothesis. An erratum to this article is available at .